A Multiple Input Multiple Output (MIMO) technology plays a very important role in improving a peak rate and a system spectrum utilization rate, so such a wireless access technology standard as Long Term Evolution (LTE) or LTE-Advanced (LTE-A) is established on the basis of a Multiple Input Multiple Output and Orthogonal Frequency Division Multiplexing (MIMO+OFDM).
In addition, for the MIMO technology, its performance gain is derived from a spatial freedom degree capable of being acquired by a multi-antenna system, so the most important development direction of the standardization of the MIMO technology lies in the extension of dimensions. An LTE Rel-8 system may at most support the MIMO transmission through four layers. An LTE Rel-9 system focuses on the enhancement of a Multi-USER MIMO (MU-MIMO) technology, and the MU-MIMO technology with a Transmission Mode (TM)-8 may at most support four downlink data layers. In an LTE Rel-10 system, eight antenna ports are introduced, so as to improve a spatial resolution of CSI and extend a transmission capability of Single-User MIMO (SU-MIMO) to at most eight data layers.
In order to further improve the MIMO technology, a massive antenna technique has been introduced into a mobile communication system. In the related art, a massive, full-digital antenna includes up to 128, 256 or 512 antenna elements, and each antenna element is connected to a transceiver, i.e., the massive antenna may include up to 128, 256 or 512 transceivers and 128, 256 or 512 antenna ports. Due to the large quantity of transceivers, a volume of data to be transmitted may increase. For example, for 128 antenna ports, its transmission rate R is about 157286.4 Mbps, and 32 fifth-generation (5G) optical fibers needs to be provided for the data transmission. In addition, the spatial resolution of the CSI directly depends on the number of ports for a downlink reference signal, and in order to acquire channel information about each antenna port, a large number of CSI-Reference Signals (CSI-RSs) need to be provided, resulting in a large overhead of time/frequency resources.
Hence, for the massive, full-digital antenna which includes a large number of transceivers and where a large number CSI-RSs need to be provided, there is an urgent need to meet the requirement on a high transmission rate and reduce the overhead of the time/frequency resources.